WO2017025318A1

WO2017025318A1 - Method for setting a screw

Info

Publication number: WO2017025318A1
Application number: PCT/EP2016/067769
Authority: WO
Inventors: Martin Hartz; Niels Goos; Simon Velten
Original assignee: Hilti Aktiengesellschaft
Priority date: 2015-08-12
Filing date: 2016-07-26
Publication date: 2017-02-16
Also published as: CN107850102A; EP3334945A1; CN107850102B; CA2994595A1; EP3130811A1; EP3334945B1; CA2994595C; US10935065B2; US20180231045A1

Abstract

The invention relates to a method for setting a screw, which has an external thread in a front region and a drive in a rear region for introducing a torque into the screw, in a drilled hole in a substrate of a mineral material, in which method an internal thread is produced in the drilled hole by means of a threaded drill provided with a cutting thread, and then the screw is introduced into the drilled hole and in so doing the external thread of the screw is screwed into the internal thread, produced by the threaded drill, in the drilled hole. According to the invention, there is provision that the outside diameter of the cutting thread of the threaded drill is smaller than the outside diameter of the external thread of the screw. The invention further relates to packages comprising objects for carrying out such a method.

Description

Method for setting a screw

The invention relates to a method for setting a screw, which has a male thread in a front region and a drive for introducing torque into the screw in a rear region, in a borehole in a mineral building material substrate, according to the preamble of claim 1 , In such a method it is provided that

- By means of a threaded tap provided with a cutting screw, an internal thread is produced in the borehole, and

- Subsequently, the screw is introduced into the borehole, in particular screwed, and while the external thread of the screw is screwed into the taps produced by the internal thread in the borehole.

The invention further relates to containers containing articles for carrying out such a method.

From DE 19735280 A1 it is known to pre-cut a thread before screwing in a concrete screw, whereby a greater freedom in the choice of material for the concrete screw should be given.

DE 19905845 A1 describes a screw fastening set for concrete, in which a screw and a screw designed in the manner of a screw tap are provided, wherein the core diameter of the tap is smaller than the core diameter of the screw, so that the game at the core of the screw less than the play at the core of the tap. This is to be achieved, that on the one hand with the tap, the cutting flour occurring during thread cutting can be transported to the outside, and on the other hand, the screw is housed with a fixed seat in the pre-cut thread. Preferably, the outer diameter of the screw in the region of the cylindrical thread should be smaller than the outer diameter of the tap, which is to be achieved so that when screwing the screw into the thread no clamping on the outer circumference of the thread of the screw occur. From EP 0625400A1 a tool for generating an internal thread in concrete, masonry or the like emerges.

The US 4439077 A describes a concrete screw, which is designed so that when screwing drilling dust is compacted. Another concrete screw is known from US 4842467A.

US 8696477 A, US 8182185 A, US 7740435 A, US 8182186 A and US Pat. No. 7484920 A disclose concrete screws which, when threaded, have cutting bodies which have a higher hardness than the rest of the thread. This makes it possible to use a material with a comparatively high corrosion resistance for the remaining screw areas, even if this should have a comparatively low hardness.

The object of the invention is to provide a method for setting a screw in a borehole in a substrate made of a mineral building material, in particular concrete, with which a particularly reliable setting of the screw is possible with little effort, and with the particularly good load values and a Particularly good corrosion resistance can be achieved, as well as containers containing items to perform such a method.

The object is achieved by a method with the features of claim 1 and container with the features of claims 8 and 9. Preferred embodiments are given in the dependent claims.

An inventive method is characterized in that the outer diameter of the cutting thread of the tap is smaller than the outer diameter of the external thread of the screw.

A basic idea of the invention can be seen in the use of the tap to cut an internal thread in the borehole, into which the external thread of the screw is subsequently screwed, wherein the cutting thread of the tap is dimensioned so that the pre-cut internal thread against the external thread of the screw has a lesser degree.

In the context of the invention it has been observed that it is when setting screws in mineral materials, especially in high or ultra high strength concrete and especially At Armierstreffern, may come to an undesirable blocking of the screw. This has been observed in particular with screws with cutting bodies in the thread path, and may be due to an undesirable interaction of the surfaces of the cutting body and / or the surfaces of the provided for the cutting body thread recesses with the substrate. In addition, it has been observed within the scope of the invention that armament hits can result in high wear or, in extreme cases, complete destruction of the thread helix, which can lead to performance losses or, in extreme cases, to spin-through, whereby the attachment point can become unusable. This is where the invention comes in and provides, according to a first idea of the invention, to pre-cut in the concrete substrate by means of a tap a preliminary thread, namely the external thread. As a result, the abovementioned blocks and the abovementioned undesired increased wear, in particular in the case of armament hits, can be counteracted simply, so that a particularly high level of reliability is provided. According to a second basic idea of the invention, the pre-thread has a reduced mass relative to the external thread of the screw, that is to say the thread produced with the tap is smaller in its external diameter than the external screw diameter. Due to this reduction in dimension, the thread crest of the external thread of the screw cuts into the substrate when the screw is screwed in, so that loosely formed substrate particles are produced when the screw is screwed in. These substrate particles, in turn, can provide for an advantageous compression of the screw with the surrounding borehole wall, which stabilizes the borehole and therefore can provide particularly good load values. According to the invention, particularly high load values can thus be obtained with particularly high reliability.

Under the outer diameter of a thread can be understood in the usual way in particular the diameter of a thread enveloping cylinder. The cutting thread of the tap and / or the external thread of the screw are preferably cylindrical thread. The outer diameter of the cutting thread of the tap is preferably constant over at least 50%, preferably over at least 75% or 80%, of the thread length of the cutting thread of the tap. Alternatively or additionally, the outside diameter of the external thread of the screw is preferably constant over at least 50%, preferably over at least 75% or 80%, of the thread length of the external thread of the screw.

The substrate of a mineral building material may in particular be a concrete substrate. The tap preferably has a shaft on which the cutting thread is arranged. The screw also preferably has a shaft on which the outer thread is arranged. Time between the generation of the internal thread in the borehole and the subsequent screwing the screw, one or more intermediate steps, such as cleaning steps, can be provided. Preferably, these intermediate steps leave the structure of the substrate, in particular the structure of the internal thread produced by the tap, at least approximately unchanged. The tap may preferably machine the substrate to produce the external thread.

The cutting thread of the tap and the external thread of the screw are in particular gleichsinning.

It is particularly preferred that the outer diameter of the cutting thread of the tap is 0.85 times to 0.92 times the outer diameter of the external thread of the screw. Experiments have shown that in this area, on the one hand, a particularly good load bearing capacity is given because substrate particles, which are needed for pressing in the borehole, are available to a sufficient extent, and on the other hand, a particularly good setting behavior is given. In particular, the screw is relatively easy to set, but it does not fall into the well, that is, it is given a solid seating feeling.

A further advantageous embodiment is that the thread pitch of the cutting thread of the tap by less than 3%, preferably less than 1%, deviates from the thread pitch of the external thread of the screw. This can further improve reliability and performance.

Furthermore, it is preferred that the core diameter of the cutting thread of the tap deviates by less than 3%, preferably less than 1%, from the core diameter of the external thread of the screw. As a result, the reliability can be further increased and in particular an undesired damage to the borehole can be counteracted.

In particular, it may be provided that the thread length of the cutting thread of the tap deviates by less than 3%, preferably less than 1%, from the thread length of the external thread of the screw. Hereby, the reliability can be further increased, since this can be ensured in a particularly simple manner that the Vorgewinde has the correct depth. Conveniently, at the same time an attachment to the substrate is set when screwing the screw, preferably by the screw is introduced through a recess in the attachment through into the wellbore. Thus, therefore, the attachment is set at the first screwing in the screw at the same time. As a result, the reliability can be increased even further, since it can be ensured in a particularly simple manner that substrate particles which accumulate during the widening of the preliminary thread actually contribute to the compression and thus to an increase in load capacity of the screw. Preferably, the attachment can be positively secured to the substrate, for example by a screw head provided in the rear region of the screw.

The drive may, for example, be a screw head, that is to say in particular a locally enlarged cross section of the screw. The screw head can have an outer polygon or a polygon socket. The drive can also be a simple polygon socket.

The invention also relates to a container containing a screw and / or a tap, and also containing an instruction for use, which teaches a method according to the invention using the screw or the tap. The container thus contains an instruction manual which teaches the method steps according to the invention, as well as at least one of the items required for carrying out the method. In particular, the teaching for carrying out the method according to the invention can be written down in the instructions for use. Under a container can be understood in the usual way in particular the entirety of packaging and the packaged goods.

The invention also relates to a container containing the essential objects for carrying out the method, that is containing a screw for screwing into a borehole in a substrate of a mineral building material, wherein the screw in a front region an external thread and in a rear region a drive for Introducing a torque in the screw, and provided with a cutting screw tap, wherein the outer diameter of the cutting thread of the tap is smaller than the outer diameter of the external thread of the screw.

Features mentioned in connection with the method according to the invention can also be used in the containers according to the invention, just as, conversely, features mentioned in connection with the containers according to the invention can also be used in the method according to the invention. The invention will be explained in more detail below with reference to preferred embodiments, which are shown schematically in the accompanying figures, wherein individual features of the embodiments shown below can be realized in the context of the invention, in principle, individually or in any combination. In the figures show schematically:

FIGS. 1

to 4: schematic representations of successive stages in the implementation of the inventive method;

Figure 5: a detailed view of the tap, which in the method according to FIGS

1 to 4 is used, viewed from the side;

FIG. 6 shows a detail view of the screw which is used in the method according to FIGS. 1 to 4, viewed from the side; and

Figure 7: a schematic view of a container according to the invention.

Figures 1 to 4 show different stages in the implementation of a method according to the invention.

First, in the method, as shown in FIG. 1, a preferably at least approximately cylindrical borehole 2 is provided in a substrate 1 made of a mineral building material, in particular concrete.

Then, as shown in FIG. 2, a tap 10 is inserted into the borehole 2. The tap 10 has a preferably at least approximately cylindrical shaft 15 and a helical cutting thread 16, which is arranged on the shaft 15. In a rearward region, the tap 10 has a drive 11, which is shown by way of example as a head, in particular a hexagon head, for introducing a torque into the shaft 15. The cutting thread 16 has an outer diameter 0da _s (see Figure 5), which is greater than the inner diameter of the borehole 2. Therefore, the cutting thread 16 cuts when screwing the tap 10 into the borehole 2 in the borehole 2 surrounding substrate 1 and produces an internal thread 19 in the borehole 2. For a particularly easy screwing of the tap 10 in the borehole 2, the core diameter 0dk _{s of} the cutting thread 16 of the tap 10 (see FIG. 5) may preferably be smaller than the inside diameter of the borehole 2. In the next step, as shown in Figure 3, the tap 10 is unscrewed by opposing rotation back out of the wellbore. The internal thread 19 remains in the borehole 2 back.

Then, as shown in FIG. 4, an attachment 9 is arranged in front of the borehole 2 and a screw 20 is introduced through a recess in the attachment 9 into the borehole 2. The screw 20 has a preferably at least approximately cylindrical shaft 25 and a helical external thread 26, which is arranged on the shaft 25. In a rearward region, the screw 20 has a drive 21, which is shown as a head, in particular a hexagon head, for introducing a torque into the shaft 25 and for holding the attachment 9 in a form-locking manner.

The external thread 26 of the screw 20 has an outer diameter 0da (see Figure 6), which is greater than the outer diameter 0da _{s of} the cutting thread 16, and thus is greater than the outer diameter of the inner thread 19 produced by the cutting thread 16 in the borehole 2. As a result the internal thread 19 when screwing in the screw 20 a piece radially expanded. In this case, 2 loose substrate particles fall down in the borehole, which can provide for a compression of the shank 25 of the screw and thus a radial support of the borehole 2, whereby particularly good load values for the screw 20 can be obtained. For a particularly easy screwing of the screw 20 into the borehole 2, the core diameter 0dk of the external thread 26 of the screw 20 (see FIG. 6) may preferably be smaller than the inside diameter of the borehole 2.

As shown in particular in FIGS. 5 and 6, the following relationships apply to the cutting thread 16 of the tap 10 and the external thread 26 of the screw 20, the subscript "S" in each case specifying the parameter of the tap 10 in the following:

For the outer diameter 0da _{s of} the cutting thread 16 of the tap 10 or the outer diameter 0da of the external thread 26 of the screw 20:

0da _s <0da,

preferably 0da _s <0.92 x 0da and / or 0da _s > 0.85 x 0da

For the thread length L _{s of} the cutting thread 16 of the tap 10 or the thread length L of the external thread 26 of the screw 20 is preferred: L _s = L ± 3%, preferably L _s = L ± 1%

For the thread pitch P _{s of} the cutting thread 16 of the tap 10 or the thread pitch P of the external thread 26 of the screw 20 is preferred:

P _s = P ± 3%, preferably P _s = P ± 1%.

For the core diameter 0dk _{s of} the cutting thread 16 of the tap 10 or the core diameter 0dk of the external thread 26 of the screw 20 is preferred:

0dk _s = 0dk ± 3%, preferably 0dk _s = 0dk ± 1%.

FIG. 7 shows a schematic view of a container 90 according to the invention, which contains a screw 20, a tap 10 and an operating instruction 100, wherein the operating instructions 100 describe a method according to the invention.

Claims

A method of setting a screw (20) having a male thread (26) in a front area and a drive (21) in a rear area for introducing a torque into the screw (20) in a borehole (2) in FIG a substrate (1) of a mineral building material, in which

- By means of a cutting screw (16) provided with a tap (10), an internal thread (19) in the borehole (2) is generated, and

- Subsequently, the screw (20) is introduced into the borehole (2) and while the external thread (26) of the screw (20) in the taps (10) generated by the internal thread (19) in the borehole (2) is screwed,

characterized,

that the outer diameter (0da _s ) of the cutting thread (16) of the tap (10) is smaller than the outer diameter (0da) of the external thread (26) of the screw (20).

2. The method according to claim 1,

characterized,

that the outer diameter (0da _s ) of the cutting thread (16) of the tap (10) is 0.85 times to 0.92 times the outer diameter (0da) of the external thread (26) of the screw (20).

3. The method according to any one of the preceding claims,

characterized,

the thread pitch (P _s ) of the cutting thread (16) of the tap (10) differs by less than 3% from the thread pitch (P) of the external thread (26) of the screw (20).

4. The method according to any one of the preceding claims,

characterized,

the core diameter (0dk _s ) of the cutting thread (16) of the tap (10) deviates by less than 3% from the core diameter (0dk) of the external thread (26) of the screw (20).

5. The method according to any one of the preceding claims,

characterized,

the thread length (L _s ) of the cutting thread (16) of the tap (10) differs by less than 3% from the thread length (L) of the external thread (26) of the screw (20).

6. The method according to any one of the preceding claims,

characterized,

that when screwing in the screw (20) at the same time an attachment (9) on the substrate (1) is fixed.

7. The method according to any one of the preceding claims,

characterized,

the drive (21) is a screw head.

8. containing containers (90)

a screw (20) and / or a tap (10), and further comprising an instruction manual (100) teaching a method according to any one of claims 1 to 7 using the screw (20) and the tap (10), respectively.

9. containing containers (90)

a screw (20) for screwing into a borehole (2) in a substrate (1) of a mineral building material, wherein the screw (20) in a front region an external thread (26) and in a rear region a drive (21) for Introducing a torque in the screw (20), and

a tap provided with a cutting thread (16) (10),

characterized,